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- This is a draft version of my Fast Hartley Transform (FHT) routine for KolibriOS
- Hartley transform is a real-basis version of well-known Fourier transform:
- 1) basis function: cas(x) = cos(x) + sin(x);
- 2) forward transform: H(f) = sum(k=0..N-1) [X(k)*cas(kf/(2*pi*N))]
- 3) reverse transform: X(k) = 1/N * sum(f=0..N-1) [H(f)*cas(kf/(2*pi*N))]
- FHT is known to be faster than most conventional fast Fourier transform (FHT) methods.
- It also uses half-length arrays due to no need of imaginary data storage.
- FHT can be easily converted to FFT (and back) with no loss of information.
- Most of general tasks FFT used for (correlation, convolution, energy spectra, noise
- filtration, differential math, phase detection ect.) may be done directly with FHT.
- ====================================================================================
- Copyright (C) A. Jerdev 1999, 2003 and 2010.
- The code can be used, changed and redistributed in any KolibriOS application
- with only two limitations:
- 1) the author's name and copyright information cannot be deleted or changed;
- 2) the code is not allowed to be ported to or distributed with other operation systems.
- 18/09/2010
- Artem Jerdev <kolibri@jerdev.co.uk>